Ultrasonic transducers have been employed in ultrasound therapy systems to achieve therapeutic heating of diseased and other tissues. Arrays of ultrasound transducers operating to form a beam of ultrasonic energy cause a conversion of sound to thermal energy in the affected tissue areas or treatment volumes, and a subsequent beneficial rise in the temperature in the treatment volumes. With proper monitoring of the heating effect, ultrasound therapy systems can be used to treat harmful cells and to controllably destroy cancerous tumors.
As known to those skilled in the art, ultrasonic transducers are constructed and operated to take electrical power and produce ultrasound energy waves from a surface of a transducer element in a process generally referred to as transduction. The nature and extent of the transduction depends on the material used to construct the transducers, transducer geometry, and the electrical input to the transducers. A common material used in construction of ultrasound transducers is piezo-electric transducer crystal material (lead zirconate titanate, PZT) which comes in several forms.
In general, a higher power electrical supply input results in a greater acoustic (ultrasonic) output from the transducers. However, the precise form of the optimal electrical supply power to ultrasound transducer elements and systems can be difficult to determine in advance of use of the systems. Also, it is difficult to determine the exact power and efficiency of ultrasound therapy systems using present techniques. In addition, it has been difficult or impossible to accurately measure the electrical input power and effectiveness of electrically-driven ultrasound therapy transducers and systems. Factors such as design and material variability, as well as real-time variability within the system and the patient can cause drift or uncertainty in the electrical behavior of ultrasound treatment systems.
It is therefore useful to have improved ways of provisioning electrical power to ultrasound therapy systems and transducers. It is also useful to be able to measure the electrical power needs and usages of such transducers and systems with more accuracy in clinical therapy systems where accurate power deposition into the target tissues may help avoid unwanted results of ultrasound therapy procedures.